JP2020083087A - Driving support system - Google Patents

Abstract

To reduce damages by performing vehicle control according to the presence/absence of a front obstacle and a characteristic when there is a possibility of a rear-end collision from a rear vehicle in a stop state in which a vehicle cannot control the movement of the own vehicle.SOLUTION: A vehicle control device (collision control ECU) 205 compares brake hydraulic pressure of a vehicle with a prescribed threshold value when there is a possibility of a rear-end collision from a rear vehicle by a first sensor which is provided in the vehicle to detect a rear obstacle in a stop state of the vehicle and a front obstacle is detected by a second sensor which is provided in the vehicle to detect the front obstacle. When the brake pressure of the vehicle is less than the prescribed threshold value, a brake control device (brake ECU) 208 is controlled so that the brake hydraulic pressure of the vehicle becomes equal to or larger than the prescribed threshold value.SELECTED DRAWING: Figure 2

Description

The present invention relates to a driving support system, and more particularly to a driving support system that reduces collision damage when there is a possibility of a rear-end collision from a rear vehicle in a stopped state where the vehicle cannot control the movement of the vehicle.

As an example of vehicle control for collision prevention, in pre-crash brake control, when the driving support computer has a high possibility of collision with a detected collision object such as a preceding vehicle or a road structure, "Brake! "Prompt the driver with a warning by issuing a display or alarm. Further, when it is determined that the collision is inevitable, the brake is automatically operated.

Not only the control for the obstacle in front, but also the rear pre-crash control for the collision with the rear vehicle approaching from the rear is performed. In this rear pre-crash control, when a rear vehicle approaches, for example, headrest control for whiplash prevention is performed, and a hazard lamp is blinked to call attention to the rear vehicle.

Specifically, when the driving support computer detects that a rear vehicle is approaching by a millimeter wave radar sensor on the rear side and determines that there is a high possibility of a rear-end collision, it transmits an operation request signal to the microcomputer that controls the headrest. .. Upon receiving the operation request signal, the headrest control microcomputer drives a motor built in the headrest to move the headrest forward, and also performs control to restore the original state when there is no collision (headrest control). Alternatively, a request signal for blinking a hazard lamp, which is an alarm to the vehicle behind, is transmitted to the main body ECU (Electronic Control Unit). The main body ECU that has received the lighting request signal blinks the hazard lamp via the flasher relay (hazard lamp blink control).

In Patent Document 1, as an example of such collision control, the drive torque of the drive motor is increased from the time when it is determined that the collision of the rear following vehicle cannot be avoided to the time when the rear following vehicle collides. Accordingly, there is disclosed a collision impact reducing device that reduces the relative speed of the rear following vehicle and reduces the impact when the rear following vehicle collides rearward.

JP, 2005-113760, A

When a rear-end collision accident occurs in the stopped vehicle, the brake may not be applied due to a change in the driver's riding posture due to the impact, a mental shock, or the like. At this time, the own vehicle is pushed out by the rear vehicle, which may cause a collision with a stopped vehicle in front of the own vehicle or a person crossing the intersection. The present invention is intended to mitigate a collision damage to a person in front of a vehicle or a vehicle ahead of the vehicle, which is caused by the forward movement of the own vehicle due to the rear-end collision of the vehicle behind.

A vehicle driving support system that is an embodiment of the present invention includes a vehicle control device that detects the possibility of a vehicle colliding with an obstacle and controls the vehicle, and a brake control device that controls the brake hydraulic pressure of the vehicle. When the vehicle is in a stopped state, the vehicle control device has a possibility that a rear vehicle may collide with the rear vehicle by the first sensor that detects a rear obstacle provided in the vehicle, and the front obstacle provided in the vehicle. When a front obstacle is detected by the second sensor for detecting the vehicle pressure, the brake hydraulic pressure of the vehicle is compared with a predetermined threshold value, and when the brake hydraulic pressure of the vehicle is less than the predetermined threshold value, The brake control device is controlled so that the brake hydraulic pressure is equal to or higher than a predetermined threshold value.

When there is a possibility of a rear-end collision from a rear vehicle in a stopped state where the vehicle cannot control the movement of the vehicle, vehicle damage is reduced by controlling the vehicle according to the presence and characteristics of a front obstacle.

Other problems and novel features will be apparent from the description of the present specification and the accompanying drawings.

It is a figure which shows the frontal collision accident occurrence condition by a rear-end collision. It is a functional block diagram of a driving support system. It is a flowchart which shows the operation procedure of a driving assistance system.

FIG. 1 is a diagram showing a front collision accident occurrence situation due to a rear-end collision, which is supposed to be supported by the driving support system according to the present embodiment. The vehicle 100 detects at least one of a driving support system, a millimeter-wave radar for detecting an obstacle in the front area 103, a camera, or LIDAR (Light Detection and Ranging), and an obstacle in the rear area 104. It is equipped with a millimeter wave radar.

In a frontal collision accident due to a rear-end collision, when the vehicle 100 is stopped at a red traffic light, slows down, or is in a traffic jam, etc. The vehicle 100 is pushed forward and collides with an obstacle in front of it (a front obstacle, a person 101 in this example).

FIG. 2 shows a functional block diagram of the driving support system 212 mounted on the vehicle 100. A collision control ECU (Electronic Control Unit) 205 is connected to a front millimeter wave radar (or ultrasonic sensor) 201, a camera 202, a LIDAR 203, and a rear millimeter wave radar 204 via a communication line 200, and a communication line 206. The brake ECU 208, the vehicle speed sensor 209, and the steering ECU 210 are connected via the. Data is transmitted and received between the respective processing blocks via the communication line 200 or the communication line 206 using a protocol such as CAN (Controller Area Network). Hereinafter, each processing block will be described.

The front millimeter-wave radar 201 uses a millimeter wave having a wavelength of 1 to 10 mm and a very high frequency of 30 to 300 GHz, and the relationship between the time required from the transmission of the radar to the reception of the reflected wave from the object and the speed of light. The distance measurement function calculates the distance from the sensor to the target object by calculating, and measures the distance to the obstacle in front of the radar or to the side, and the speed measurement function to measure the speed to the obstacle. The front millimeter wave radar 201 is a pre-crash safety system (pre-crash safety system) for executing a warning and a display for a driver to avoid a collision with a front obstacle, and further automatic deceleration control, and an automatic traveling control ( It is also used for ACC: Adaptive Cruise Control). The detection range of the millimeter wave radar is 100 m, for example.

An ultrasonic sensor may be used to detect the front obstacle. An ultrasonic sensor is a sensor that uses ultrasonic waves to detect obstacles in front of it, and the ultrasonic wave is transmitted toward the object by a wave transmitter, and the reflected wave is received by the wave receiver to detect the object. The presence or absence and the distance to the object are detected. Specifically, the distance from the sensor to the object is calculated by calculating the relationship between the time required from the transmission of the ultrasonic wave to the reception of the reflected wave from the object and the speed of sound. However, the detection range of the ultrasonic sensor is generally narrower than that of the millimeter wave radar sensor.

The camera 202 detects an object from the captured image and classifies the detected object type. For example, it has a function of recognizing the characteristics of a person from an image and determining whether the front obstacle is a person or a person other than the person. The camera 202 has high accuracy in determining the type of object, but is easily affected by the weather.

Furthermore, it is also possible to use the LIDAR 203 to determine the front obstacle. The LIDAR 203 can measure scattered light with respect to pulsed laser irradiation and analyze the distance to a long-distance object and the property of the object. The short-range LIDAR has an advantage that it is less susceptible to the weather than the camera.

The rear millimeter-wave radar 204 is a sensor that detects a vehicle approaching from the rear, and uses the same function as the front millimeter-wave radar 201 to calculate the distance to the rear obstacle and the speed with respect to the obstacle.

The vehicle speed sensor 209 outputs a pulse signal according to the rotation speed of the wheels to the collision control ECU 205. The collision control ECU 205 calculates the vehicle speed based on the pulse signal output by the vehicle speed sensor 209. The vehicle speed may be detected using a millimeter wave sensor, or may be calculated based on other parameters such as the rotation speed of the output shaft and the rotation speed of the output shaft of the transmission.

The brake ECU 208 transmits a control signal to the brake actuator 207, and the brake actuator 207 distributes the braking force based on the control signal from the brake ECU 208 to perform brake control. The brake ECU 208 controls the brake actuator 207 based not only on the control based on the operation signal for detecting the drive operation of the brake pedal, but also on the drive assist control as danger avoidance from the collision control ECU 205 connected via the communication line 206. Send a signal.

The steering ECU 210 transmits a control signal to an EPS (Electric Power Steering Systems) 211, and the EPS 211 performs steering control based on the control signal from the steering ECU 210. The steering ECU 210 transmits a control signal to the EPS 211 not only based on an operation signal for detecting a steering operation operation but also based on driving assistance control as a risk avoidance from the collision control ECU 205 connected via the communication line 206. To do.

Although details will be described later, the collision control ECU (vehicle control device) 205 detects an approaching object in the rear using the rear millimeter-wave radar 204, and there is a possibility that the collision control ECU (vehicle control device) 205 will collide with the rear obstacle based on the relative speed and the distance to the rear obstacle. To judge. When there is a possibility of a rear-end collision, the front millimeter wave radar (or ultrasonic sensor) 201 is used to detect the distance/relative velocity of the front collision object, and the camera 202 or LIDAR 203 is used to detect whether the front obstacle is a person or a person. Other than the above, the control operation such as whether to apply the brake for avoiding the collision and whether to turn the steering wheel is determined based on the speed signal from the vehicle speed sensor 209. The collision control ECU 205 stores the optimum control value at the time of a rear-end collision, and the state of the vehicle 100 by various sensors such as the state of the surroundings of the vehicle 100 by the above-mentioned sensor and the vehicle speed sensor 209 for detecting the speed of the vehicle 100. Is detected, the optimum value is selected from the stored control values, and the actuator of each mechanism such as the brake and the steering is controlled.

FIG. 3 is a flowchart showing the operation procedure of the driving support system according to the present embodiment. First, the collision control ECU 205 acquires rear obstacle information regarding a following vehicle approaching from behind from the rear millimeter wave radar 204, and determines the possibility of a rear-end collision (steps 302 and 303). When there is no possibility of a rear-end collision (NO in step 303), the collision control of this embodiment is not performed.

When it is determined that there is a possibility of a rear-end collision (YES in step 303), the collision control ECU 205 acquires vehicle speed information from the pulse signal from the vehicle speed sensor 209 (step 304), and the vehicle speed is γkm/h or less. It is determined whether or not (step 305). Since the collision control of this embodiment is for a vehicle in a stopped state where the movement of the own vehicle cannot be controlled immediately, step 305 sets γ=0 to determine whether or not the vehicle is in the stopped state. Alternatively, even if the vehicle 100 is moving at an extremely low speed as in the state immediately before the stop, proper avoidance is difficult and the collision control of the present embodiment is effective, so γ is set to a value slightly larger than 0. May be. When the vehicle speed is higher than γkm/h (NO in step 305), the collision control of this embodiment is not performed. If the vehicle speed is γkm/h or higher, the avoidance operation by the driver's brake control and steering control is prioritized.

When the vehicle speed is determined to be γkm/h or less (YES in step S305), the collision control ECU 205 acquires front obstacle information from the front millimeter wave radar (or ultrasonic sensor) 201, the camera 202 or the LIDAR 203 ( In step 306), it is determined whether or not there is a person in front of the vehicle by using camera information or LIDAR information (step 307).

The collision control ECU 205 detects the brake hydraulic pressure via the brake ECU 208 regardless of whether there is a person in front (whether the determination in step 307 is made) (steps 308 and 315).

When the detected brake hydraulic pressure is less than β or αMPa that is sufficient to prevent a frontal collision due to a rear-end collision (YES in step 309 or step 316), the collision control ECU 205 sets the brake hydraulic pressure to β or αMPa or more. A control signal is transmitted to the brake ECU 208 to automatically apply the pressure (step 311 or step 318). Here, the threshold value of the brake hydraulic pressure is switched depending on whether or not there is a person in front, and the threshold value satisfies the relationship of α<β, and β is a value sufficient to stop the forward movement of the vehicle body when a rear-end collision occurs. Is specified.

On the other hand, if it is determined that the brake hydraulic pressure is β or αMPa or more (NO in step 309 or step 316), the brake hydraulic pressure is sufficient to avoid the occurrence of a frontal collision accident, and therefore the current brake hydraulic pressure is maintained as it is. (Step S310 or step 317).

Further, when the collision control ECU 205 determines that there is a person ahead (YES in step 307), the collision control ECU 205 transmits a control signal to the steering ECU 210 (step 312). At this time, the EPS 211 steers the steering wheel in a direction in which no one is present, and maintains this state until it is determined in step 313 that the dangerous state has been avoided.

When the collision control ECU 205 determines that the dangerous state is avoided (YES in step 313), the collision control ends, and the steering and brake hydraulic pressures are returned to the original states (step 314). Whether or not the dangerous state has been avoided is confirmed by confirming that the rear vehicle has stopped based on the rear obstacle information, the rear obstacle cannot be recognized, or the driver has stepped on the accelerator. Can be determined by.

Although the present invention has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from the scope of the invention. .. For example, in the flowchart of FIG. 3, the values of α, β, and γ are assumed to be optimum control values stored according to the situation of a rear-end collision, but even if they are fixed values, the values are calculated by a function including variables. It may be one. Further, the state of the vehicle 100 may include information such as a load amount, and the state around the vehicle 100 may include a road surface state (slipperiness and the like). In the collision control of this embodiment, map information may be used when steering control is performed. In addition, when there is no front obstacle, it may be combined with other control for performing vehicle control that reduces the impact of a rear collision.

100: vehicle, 101: person, 102: rear vehicle, 103: front area, 104: rear area, 200, 206: communication line, 201: front millimeter wave radar, 202: camera, 203: LIDAR, 204: rear millimeter wave Radar, 205: collision control ECU, 207: brake actuator, 208: brake ECU, 209: vehicle speed sensor, 210: steering ECU, 211: EPS, 212: driving support system.

Claims (8)

A vehicle driving support system,
A vehicle control device that controls the vehicle by detecting the possibility that the vehicle collides with an obstacle,
And a brake control device for controlling the brake hydraulic pressure of the vehicle,
When the vehicle is in a stopped state, the vehicle control device may be collided by a rear vehicle with a first sensor that detects a rear obstacle provided in the vehicle, and a front obstacle provided in the vehicle. When a front obstacle is detected by a second sensor that detects the value, the brake hydraulic pressure of the vehicle is compared with a predetermined threshold value, and the brake hydraulic pressure of the vehicle is less than the predetermined threshold value. Is a driving support system for controlling the brake control device so that the brake hydraulic pressure of the vehicle becomes equal to or higher than the predetermined threshold value. In claim 1,
The vehicle control device determines whether or not the front obstacle is a person based on the output of the second sensor, and when the front obstacle is a person other than the predetermined threshold, determines whether the front obstacle is a person. The value of 1 is set to a second value when the front obstacle is a person, and the second value is larger than the first value. In claim 2,
The vehicle control device is a driving support system that determines that the vehicle is in a stopped state when the vehicle speed of the vehicle is equal to or lower than a third value. In claim 3,
The driving support system in which the first to third values are fixed values or functions that include variables are stored in the vehicle control device. In claim 1,
A steering control device for controlling the steering of the vehicle,
The vehicle control device determines whether or not the front obstacle is a person based on the output of the second sensor, and when the front obstacle is a person, steers in a direction where the person is not present. A driving support system for controlling the steering control device. In claim 1,
When the vehicle control device determines that the possibility of a rear-end collision from the rear vehicle is avoided, the vehicle control device controls the brake control device to return the brake hydraulic pressure of the vehicle to the original state. In claim 5,
When the vehicle control device determines that the possibility of a rear-end collision from the rear vehicle has been avoided, the vehicle control device controls the steering control device to return the steering of the vehicle to the original state. In claim 1,
The said 1st sensor is a millimeter wave radar, and the said 2nd sensor is a driving assistance system containing at least 1 or more of a millimeter wave radar, a camera, and LIDAR.

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